A. Field of the Invention
The present invention relates generally to rotary broom sweeper hoppers and more particularly to a rotary broom sweeper hopper with improved means for removing particles from the dust laden air stream prior to final filter interception.
B. Description of the Prior Art
Rotary broom sweepers typically include a self-propelled vehicle which carries a horizontally mounted rotating broom that is positioned to sweep material from the surface over which the sweeper travels into a dust and debris hopper. The hopper is a box-like structure having an inlet opening to receive material from the rotary broom. A filter assembly is positioned in the hopper to divide the hopper into a dust and debris receiving chamber and an exhaust chamber. The hopper includes an exhaust blower to establish a flow of air through the hopper from the inlet opening to the filter assembly.
An example of a rotary broom sweeper hopper is disclosed in Burgoon, et al. U.S. Pat. No. 4,328,014. In the hopper of the Burgoon patent the hopper inlet is positioned between the rear wall and the bottom wall and the filter assembly and exhaust blower are positioned near the rear and top walls of the hopper. Thus, the air stream enters the hopper at the lower rear and makes a sweeping 180.degree. turn along the hopper floor and front wall and migrates along the top wall of the hopper where it is finally intercepted by the filter. It is contemplated that the majority of the dirt and debris particles will be removed from the air flow stream by centrifugal force as the stream makes the 180.degree. turn. However, the uplifting action of the air stream along the front wall of the hopper sweeps a substantial number of particles across the top wall. Thus, a substantial amount of particulate matter which could have been removed by centrifigal action is retained in the air flow stream and is deposited on the filter. The excess material deposited on the filter decreases the efficiency of the filter and sweeper.
Additionally, some of the particulate matter swept along the top wall of the hopper drops to the bottom wall of the hopper. The dropped material creates a mound in the debris throw area immediately in front of the broom. This mound undesirably disrupts both the particle trajectories and air flow as dust and debris is projected into the hopper from the rotary broom. Such disruption further decreases the efficiency of the sweeper.
It is therefore an object of the present invention to provide a rotary broom sweeper hopper that overcomes the shortcomings of the prior art. More particularly, it is an object of the present invention to provide an improved rotary broom sweeper hopper in which the energy from the hopper air flow stream is utilized to increase particulate removal from the air flow stream prior to interception by the filter. It is a further object of the present invention to provide an improved rotary broom sweeper hopper in which the mound of debris and other particulate matter in the broom throw area is decreased in size or eliminated.